Animal Nutrition

Controlling Salmonella in pig farming: strategies to reduce the risk of contamination

Test tubes in a laboratory

Salmonellosis is an intestinal infection caused by Salmonella bacteria. Very common in pig farms, this bacteria is capable of infecting both animals and humans in different ways.

Because it represents a threat to food safety, since the contamination occurs from the ingestion of meat from contaminated animals, it is extremely important that farms have strict control over this type of bacteria.

Pork and its derivatives are classified as the third-largest source of Salmonella infections in humans. 

To reduce these risks, swine feed must be controlled. In addition, animal slaughter should also be done as hygienically as possible to avoid meat contamination by Salmonella.

In this blog post, we will discuss the ways to prevent the occurrence of Salmonella in pig farming and how to control this type of infection.

Prevention: the safest path

The control of Salmonella in pig farming should happen throughout the entire production chain.

However;

Due to the number of people involved in this chain as well as the epidemiological difficulties related to Salmonella, this control is far from being an easy task.

Although most Salmonella infections in pigs occur during slaughter, the control needs to start in the pig feeding. As it can also be a source of contamination. 

Although;

It is known that swine feed itself is not the main problem, once it goes through heat treatments to eliminate this type of microorganism, but rather in how the feed is manipulated as it reaches the farm. Depending on the practices used to manipulate it, cross-contamination may occur leading to Salmonella in swine feed. 

Strategies to control Salmonella in swine feed

The way the feed is provided (in pallets or not) and the type of grinding by which it has undergone (particle size) are factors that influence the intestinal microbiota of pigs, impacting the establishment and the multiplication of Salmonella in the gastrointestinal tract of the animals.

Studies have shown that non-palletized feed and feed with rougher particles provide a protective effect against Salmonella contamination. 

The physical state of the feed also has an influence on this type of infection. Feed in a liquid state, if compared to dehydrated feed, has a protective effect against Salmonella.

This effect of liquid feed is linked to epithelial cell growth stimulation, reduction of intestinal pH and increase of lactic acid bacteria in the microbial flora. Higher acidity is extremely unfavorable to the multiplication of Salmonella which, like most pathogens, has its optimum growth at near-neutral pHs.

Following this idea, it is possible to add acid substances to the feed or even to the water given to the pigs. Substances such as propionic acid, acetic acid, lactic acid, and many others can be used.

Another interesting strategy is the use of probiotics. These microorganisms are non-pathogenic anaerobic bacteria that populate the animal organism promoting beneficial effects.

Probiotics are able to reduce metabolic reactions which produce toxic substances and also stimulate the production of endogenous enzymes and vitamins. These bacteria also reduce the pH of the gastrointestinal tract, promoting a non-ideal environment to the multiplication of Salmonella.

The bacteria of the genus Streptococcus, Bifidobacterium and Lactobacillus are probiotics widely used in several areas and even though its use in pig feed is still recent, current studies are already promising.

Learn more about swines:

Ingredients for pork nutrition: 6 variables you should pay attention
How changes in swine feed may affect the weaning phase
Major diseases in swine farming: how to avoid them
How can Chicken Protein Hydrolysate improve Swine Nutrition

Hygiene and biosafety: two concepts that must go together

By now it is already clear that to develop the infection, Salmonella needs to overcome the hostile environment of the gastrointestinal tract of animals. However, in external environments, the situation is different.

Salmonella is able to adapt perfectly to external environments, surviving for extended periods of time outside its host. 

In addition, in several cases, pigs infected with Salmonella do not present any clinical symptoms, leading to a high risk of infection for healthy animals.

All these factors make environmental hygiene essential to ensure biosafety. The prevention strategies mentioned above have no use on their own, they must always be linked to strict hygiene control.  

A common practice is the cleaning and disinfection of environments every time a group of pigs leaves and another one enters.

The caution with the disinfection procedure should be full time, considering that Salmonella is able to survive for 14 days on soft metallic surfaces, 1 year when in moist soil and up to 2-4 years in dry excrement. This high survival rate in the environment greatly increases the risk of transmission.

The cleaning protocol should include the following aspects:

•  Pig housing and environment cleaning with pressurized water to remove organic matter, with special attention to cavities.
•  The use of detergent together with pressurized water to optimize the removal of organic matter.
•  Applying a disinfectant after cleaning.

Conclusion

Unfortunately, pig farming is one of the practices where Salmonella is most present. However, there are several strategies to reduce the risks of infection. From procedures related to pig feeding to hygienic actions in the swine’s environment.

Controlling the multiplication of Salmonella in the swine environment should be a top priority, whichever strategy is chosen,

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